JP6788957B2 - Generator - Google Patents

Description

The present invention relates to a generator used for a bicycle hub dynamo or the like.

Since the rotor of a bicycle hub dynamo rotates at the same speed as the wheels, the rotation speed of the rotor tends to be slower than that of the roller dynamo, and the induced electromotive force at low speed tends to be insufficient. .. Therefore, as the hub dynamo, a hub dynamo devised so that high-frequency AC power can be obtained even when the rotation speed of the rotor is low is preferably used.

As an example of this, Patent Document 1 proposes a claw pole type generator. This generator includes a stator and a rotor arranged on the outer peripheral side of the stator. The rotor has a plurality of magnets arranged side by side in the circumferential direction, and each magnet has magnetic poles facing the stator that are alternately different in the circumferential direction. The stator comprises a pair of stator cores arranged on both sides in the axial direction. Each stator core has a plurality of claws extending toward the side approaching each other, and the claws of the separate stator cores are provided so as to be alternately positioned in the circumferential direction. The claws of each stator core are arranged inside each magnet of the rotor in the radial direction, and the magnets are excited so as to alternately generate different polarities in the circumferential direction. An armature coil is arranged on the stator at a position where magnetic flux passes from the magnet through the claw portion of each stator core.

In this generator, the rotation of the rotor changes the relative position of the magnet with respect to the claws of each stator core, and the polarity of each claw is switched accordingly, so that the direction of the main magnetic flux interlinking the armature coil is changed. It reverses and an induced electromotive force is generated in the armature coil. Since the AC power obtained at this time has a frequency proportional to the number of poles of the magnet, it is easy to obtain a high frequency AC power corresponding to the number of poles of the magnet.

Japanese Unexamined Patent Publication No. 2007-94839

In recent years, in order to improve the design of a bicycle, it has been required to reduce the outer diameter of the hub, and along with this, it is desired to reduce the outer diameter of the hub dynamo. In the claw pole type generator, the claws of the stator cores excited to have different polarities are arranged alternately in the circumferential direction. Therefore, as the outer diameter of the hub dynamo becomes smaller, the distance between adjacent claws becomes excessively small. As a result, the magnetic flux easily passes between the claws excited to have different polarities, and the leakage flux that does not interlink the armature coil tends to increase. Therefore, the claw pole type generator has a problem that the leakage flux increases as the outer diameter dimension is reduced, and it is difficult to obtain a sufficient induced electromotive force.

The present invention has been made in view of such a problem, and one of the objects thereof is that it is easy to obtain high-frequency AC power even when the rotation speed of the rotor is small, and further, it is suitable for miniaturization of the outer diameter dimension. It is to provide a generator.

The generator according to an aspect of the present invention is arranged with a rotor, a plurality of magnets which are spaced apart from each other in the circumferential direction and have magnetic poles facing each other in the circumferential direction, and are arranged on both sides of the magnet in the circumferential direction. A stator core including a coil slot portion and a stator having an armature coil wound between the coil slot portions so as to straddle the magnet in the circumferential direction are provided, and the rotors are spaced apart in the circumferential direction. It has a rotor core including a plurality of rotor salient poles formed therein, and the stator core is provided in a magnetic path portion adjacent to one of the coil slot portions in the circumferential direction so as to face the rotor. It has a first stator salient pole portion and a second stator salient pole portion provided on a magnetic path portion adjacent to the other in the circumferential direction with respect to the coil slot portion so as to face the rotor.

According to the present invention, it is easy to obtain high-frequency AC power even when the rotation speed of the rotor is small, and it is possible to obtain a generator suitable for miniaturization of the outer diameter dimension.

It is a partial side view which shows the bicycle on which the bicycle generator which concerns on 1st Embodiment is mounted. It is a front view which shows the structure of the hub and the surroundings of the bicycle which concerns on 1st Embodiment. It is sectional drawing which shows the generator for a bicycle which concerns on 1st Embodiment. It is sectional drawing which shows the armature coil of the bicycle generator which concerns on 1st Embodiment. It is a figure which shows the positional relationship of the rotor salient pole portion and the stator salient pole portion which concerns on 1st Embodiment. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is zero. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is π / 2. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is π. It is a figure which shows the state which the electric angle of the generator which concerns on 1st Embodiment is 3π / 2. It is sectional drawing of the generator which concerns on 2nd Embodiment. It is sectional drawing which shows the armature coil of the generator which concerns on 2nd Embodiment. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is zero. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is π / 2. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is π. It is a figure which shows the state which the electric angle of the generator which concerns on 2nd Embodiment is 3π / 2.

Hereinafter, in the description of each embodiment, the same components are designated by the same reference numerals, and duplicate description will be omitted. Further, in each drawing, for convenience of explanation, some of the components are omitted as appropriate.

[First Embodiment]
FIG. 1 is a partial side view showing a bicycle 12 on which a bicycle generator 10 (hereinafter, simply referred to as a generator 10) according to the first embodiment is mounted. The bicycle 12 includes a front fork 18 rotatably supported by the head tube 16 of the main frame 14, and a hub shaft 20 attached to the front fork 18. A front wheel 22 as a wheel is rotatably supported on the hub shaft 20. A headlight 24 is installed on the side of the front wheel 22, and the electric power obtained by the generator 10 is supplied to the headlight 24.

The front wheel 22 has a tubular hub 26 rotatably supported by a hub shaft 20 via a bearing (not shown), a plurality of spokes 28 attached to the outer peripheral portion of the hub 26, and an outer peripheral portion of each spoke 28. It also has a rim 30 to be attached. A tire 32 is attached to the rim 30.

FIG. 2 is a front view showing the configuration of the hub 26 and the surroundings of the bicycle 12. Configurations other than the hub 26 are indicated by alternate long and short dash lines. A generator 10 serving as a hub dynamo is housed in the hub 26. Male threads 34 are formed at both ends of the hub shaft 20 in the axial direction. The hub shaft 20 is fixed to the front fork 18 together with the hub 26 by tightening the nut 36 screwed into each male screw 34.

FIG. 3 is a cross-sectional view of the generator 10. This figure is a cross-sectional view orthogonal to the axial direction of the rotation center of the rotor 40 described later, and is also a cross-sectional view taken along the line AA of FIG. The hub 26 is omitted in this figure. Further, in the following description, the terms "axial direction", "circumferential direction", and "diameter direction" may be used in explaining the positional relationship of each component of the stator 38 and the rotor 40, which will be described later. .. Of these, the "axial direction" means the axial direction of the rotation center of the rotor 40, and the "circumferential direction" and the "diameter direction" mean the circumferential direction and the radial direction with respect to the rotation center of the rotor 40, respectively.

The generator 10 includes a stator 38 that is fixed to the hub shaft 20 and a rotor 40 that is rotatably supported by the hub shaft 20. The generator 10 is an outer rotor type generator in which the rotor 40 is arranged on the outer peripheral side of the stator 38. Further, the generator 10 is a synchronous generator. The rotor 40 is rotatably provided integrally with the hub 26 which is a part of the front wheel 22. The rotor 40 can rotate in conjunction with the rotation of the front wheels 22.

The rotor 40 forms an annular shape as a whole. The rotor 40 includes a rotor core 46 including an annular base 42 and a plurality of rotor salient poles 44 provided on the inner peripheral side of the annular base 42 facing the stator 38 of the annular base 42. Have.

Each rotor salient pole 44 projects from the annular base 42 inward in the radial direction on the side facing the stator 38. Each rotor salient pole 44 is configured to have a width equivalent to a predetermined width w. The term "equivalent" here includes the case where they are completely the same and the case where they are substantially the same. The interpretation of "equivalent" is the same as follows.

The rotor salient poles 44 are arranged at positions shifted in the circumferential direction at an angle equivalent to a predetermined angle λ (hereinafter, also referred to as salient pole pitch) at intervals. In this example, a total of 20 rotor salient poles 44 are provided, and the salient pole pitch λ is set to 18 ° (= 360 ° / 20). This salient pole pitch λ corresponds to the electric angle 2π of the generator 10, and when the rotor 40 rotates by the salient pole pitch λ, the armature coil 60 generates AC power for one cycle as described later.

The stator 38 forms an annular shape as a whole. The stator 38 has a plurality of magnets 48 arranged at intervals in the circumferential direction, and a plurality of stator cores 50A and 50B arranged one by each of the plurality of magnets 48. The plurality of magnets 48 and the plurality of stator cores 50A and 50B are alternately arranged in the circumferential direction and are joined by adhesion or the like to form an annular shape. In this example, a total of four magnets 48 and the stator cores 50A and 50B, that is, an even number of magnets 48 are provided.

The magnet 48 is a permanent magnet. The magnet 48 is used for the field of the armature coil 60 described later. The circumferential direction of the magnet 48 is the magnetizing direction. The magnets 48 are arranged at intervals at positions shifted by the same angle in the circumferential direction. The magnetic poles of the plurality of magnets 48 adjacent to each other in the circumferential direction have the same poles. The magnet 48 is provided in a plate shape extending along the radial direction so as to divide the stator cores 50A and 50B adjacent to each other in the circumferential direction in the radial direction.

The stator cores 50A and 50B and the rotor core 46 described above are configured by laminating a plurality of metal plates in the axial direction of the rotor 40. This metal plate is made of a soft magnetic material such as an electromagnetic steel plate.

The stator cores 50A and 50B are adjacent to one of the circumferential directions (clockwise in the drawing) with respect to one magnet 48 (for example, the magnet 48 on the upper side in the drawing) arranged every other in the circumferential direction. It includes a first stator core 50A and a second stator core 50B adjacent to the other magnet 48 in the circumferential direction (counterclockwise in the drawing). In this example, two first stator cores 50A and two second stator cores 50B are provided.

Each of the stator cores 50A and 50B has coil slot portions 52 arranged on both sides in the circumferential direction of magnets 48 arranged every other in the circumferential direction. One coil slot portion 52 is arranged between the plurality of magnets 48. One coil slot portion 52 is formed for each of the first stator core 50A and each second stator core 50B. The coil slot portion 52 is formed so as to be recessed from the radial outer side on the side facing the rotor 40 to the radial inner side on the opposite side.

In addition to the coil slot portion 52, the stator cores 50A and 50B have an arcuate magnetic circuit connection portion 54 adjacent to the bottom side of the coil slot portion 52 and adjacent to both sides in the circumferential direction with respect to the coil slot portion 52. It has magnetic path portions 56A and 56B. The magnetic path connecting portion 54 connects the magnetic path portions 56A and 56B in the circumferential direction. The magnetic path portions 56A and 56B extend radially outward on the side facing the rotor 40. The magnetic path portions 56A and 56B are adjacent to the first magnetic path portion 56A adjacent to one of the circumferential directions of the coil slot portion 52 (clockwise in the drawing) and the other in the circumferential direction (counterclockwise in the drawing). Includes the second magnetic path portion 56B.

FIG. 4 is a cross-sectional view showing the armature coil 60 of the generator 10. In this figure, the winding direction B of the armature coil 60 in one of the axial directions of the rotor 40 (the front side of the paper surface) is also shown. The stator 38 further has an armature coil 60 wound between coil slot portions 52 adjacent to each magnet 48 on both sides in the circumferential direction so as to straddle each of the magnets 48 in the circumferential direction. The armature coil 60 is provided corresponding to each of the plurality of magnets 48, and the same number as the number of magnets 48 is provided. The armature coil 60 is wound so as to surround the corresponding magnet 48 from both sides in the circumferential direction and both sides in the axial direction.

The armature coil 60 is wound in a concentrated winding between the coil slot portions 52 adjacent to each other in the circumferential direction, but may be wound in a distributed winding so as to pass through another coil slot portion 52. The armature coils 60 adjacent to each other in the circumferential direction are wound in the winding directions B opposite to each other, but they may be wound in the same direction.

As will be described later, the armature coil 60 generates in-phase AC power when the rotor 40 rotates. Each armature coil 60 is electrically connected in parallel, its output end is connected to a rectifier circuit (not shown), and single-phase AC power is output to the rectifier circuit. The rectifier circuit rectifies and smoothes AC power to convert it into DC power, and then supplies this to the headlight 24 (see FIG. 1) as an external electric device. The armature coils 60 may be electrically connected in series.

Here, as shown in FIG. 3, the stator 38 includes a first stator salient pole 62A provided in each of the plurality of first magnetic path portions 56A so as to face the rotor 40, and a plurality of second magnetic paths. Each of the road portions 56B has a second stator salient pole portion 62B provided so as to face the rotor 40. The stator salient poles 62A and 62B project from the magnetic path portions 56A and 56B toward the outside in the radial direction on the side facing the rotor 40. Two first stator salient poles 62A are provided for each first magnetic path 56A, and two second stator salient poles 62B are provided for each second magnetic path 56B. In this example, a total of 16 stator salient poles 62A and 62B are provided.

The stator salient poles 62A and 62B are arranged with a predetermined gap in the radial direction with respect to the rotor salient pole 44. The stator salient poles 62A and 62B are configured to have a width equivalent to the width w of the rotor salient pole 44.

FIG. 5 is a diagram showing the positional relationship between the rotor salient pole portion 44 and the stator salient pole portions 62A and 62B. In this figure, in order to distinguish a part of the plurality of salient poles, alphabets such as (a) are added to the end of each code. The same may be shown in the following figure.

A plurality of first stator salient poles 62A provided in one first magnetic path portion 56A are arranged at positions shifted in the circumferential direction at an angle equivalent to the salient pole pitch λ of each rotor salient pole portion 44. .. A plurality of second stator salient poles 62B provided in one second magnetic path portion 56B are also arranged at positions shifted in the circumferential direction at an angle equivalent to the salient pole pitch λ. Further, the other second stator salient poles 62B adjacent to each other in the circumferential direction in the vicinity of the first stator salient pole 62A are arranged at positions shifted in the circumferential direction at an angle equivalent to λ × 1.5. ..

As a result, the first stator salient pole portion 62A is displaced in the circumferential direction at an angle equivalent to λ × n with respect to the other first stator salient pole portion 62A when n is a natural number of 1 or more. Placed in position. For example, the first stator salient pole 62A (d) is λ × 4 (= λ × 1.5 + λ + λ × 1.) With respect to other first stator salient poles 62A (g) adjacent to each other in the clockwise direction. It is deviated at 5), and is deviated by λ × 1.0 with respect to the other first stator salient poles 62A (c) adjacent to each other in the counterclockwise direction. Similarly, the second stator salient pole portion 62B is also arranged at a position shifted in the circumferential direction at an angle equivalent to λ × n with respect to the other second stator salient pole portion 62B.

Further, the second stator salient pole portion 62B is arranged at a position shifted in the circumferential direction at an angle equivalent to λ × (n + 0.5) with respect to the first stator salient pole portion 62A. For example, the second stator salient pole portion 62B (e) is displaced by λ × 2.5 (= λ + λ × 1.5) with respect to the first stator salient pole portion 62A (g) adjacent to the clockwise direction. It is offset by λ × 1.5 with respect to the first stator salient poles 62A (d) adjacent to each other in the counterclockwise direction.

The operation of the generator 10 described above will be described with reference to FIGS. 6 to 9. Each figure shows a state when the rotor 40 is rotated in the direction P by π / 2 at an electric angle. Further, in FIGS. 6 and 8, among the magnetic fluxes flowing through the rotor core 46 and the like, the flow of the main magnetic flux is mainly shown, and the flow of the leakage flux is omitted. Further, FIGS. 7 and 9 show the flow of the leakage flux. In the following, it is assumed that the electric angle is zero when the positional relationship is shown in FIG. 6, and the electric angles are π / 2, π, and 3π / 2 in FIGS. 7 to 9. Further, for convenience, one rotor salient pole portion 44 (a) is indicated by a “◯” mark.

As shown in FIG. 6, when the electric angle is zero, the first stator salient pole portion 62A has the total width in the circumferential direction with respect to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it overlaps. Further, the second stator salient pole portion 62B is displaced in the circumferential direction at a position where it does not overlap the rotor salient pole portion 44 in the vicinity thereof over the entire width in the circumferential direction when viewed from the radial direction of the rotor 40. Is in the right position. In other words, the range in which the first stator salient pole 62A overlaps with one nearby rotor salient pole 44 in the circumferential direction (hereinafter referred to as the first overlapping range) is the second stator salient pole portion. 62B is larger than the range in which the rotor salient pole portion 44 in the vicinity overlaps in the circumferential direction (hereinafter, referred to as the second overlapping range). As a result, from the first magnetoresistive R1 which is the magnetic resistance between the first stator salient pole portion 62A and the rotor salient pole portion 44, between the second stator salient pole portion 62B and the rotor salient pole portion 44. The second magnetic resistance R2, which is a magnetic resistance, becomes significantly large.

As a result, due to the magnetic flux generated from one magnet 48, the first stator salient pole 62A of the first stator core 50A adjacent to one magnetic pole surface of the magnet 48 and the second stator adjacent to the other magnetic pole surface are fixed. A closed-loop magnetic path Mp is formed that passes through the first stator salient pole portion 62A of the child core 50B. For example, the magnet 48 (b) on the upper side in the drawing is the magnetic path connection portion 54 of the first stator core 50A (b) → the first magnetic path portion 56A of the first stator core 50A (b) → the first stator. Salient pole 62A (g) → rotor salient pole 44 (g) → annular base 42 of rotor 40 → rotor salient pole 44 (c), (d) → first stator salient pole 62A (c) ), 62A (d) → A magnetic path Mp that returns to the original magnet 48 (b) via the first magnetic path portion 56A of the second stator core 50B (a) is formed.

The magnetic path Mp is formed so as to interlink in each armature coil 60 in the radial direction. At this time, since the magnetic poles of the plurality of magnets 48 facing each other in the circumferential direction are the same pole, the rotation directions of the magnetic paths Mp generated by the magnets 48 adjacent to each other in the circumferential direction are opposite to each other. For example, the magnetic path Mp generated by the magnet 48 (b) on the upper side in the figure is counterclockwise, and the magnetic path Mp generated by the magnet 48 (b) on the left side in the figure is clockwise. As a result, the magnetic fluxes generated by the different magnets 48 are linked in the same direction in one armature coil 60. For example, in the armature coil 60 (b) on the upper side in the figure, the magnetic flux generated by the magnet 48 (b) on the upper side in the figure and the magnetic flux generated by the magnet 48 (a) on the left side in the figure are chained in the same direction. Be made to.

As shown in FIG. 7, when the electric angle is π / 2, the first stator salient pole portion 62A is peripheral to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it overlaps approximately half the width of the direction. The same applies to the second stator salient pole portion 62B. In other words, the first overlapping range of the first stator salient pole portion 62A with respect to the rotor salient pole portion 44 and the second overlapping range of the second stator salient pole portion 62B with respect to the rotor salient pole portion 44 are equivalent. .. As a result, the first reluctance R1 and the second reluctance R2 have the same magnitude.

As a result, due to the magnetic flux generated from one magnet 48, the second stator salient pole 62B of the first stator core 50A adjacent to one magnetic pole surface of the magnet 48 and the second stator adjacent to the other magnetic pole surface are fixed. A closed-loop magnetic path Mp is formed that passes through the first stator salient pole portion 62A of the child core 50B. For example, the magnet 48 (b) on the upper side in the drawing is the second magnetic path portion 56B of the first stator core 50A (b) → the second stator salient pole portion 62B (e), (f) → the rotor salient pole. Parts 44 (e), 44 (f) → annular base 42 of rotor 40 → rotor salient poles 44 (c), 44 (d) → first stator salient poles 62A (c), (d) → A magnetic path Mp that returns to the original magnet 48 (b) via the first magnetic path portion 56A of the second stator core 50B (a) is formed. The magnetic path Mp reciprocates in each armature coil 60 in the radial direction, and is formed so as not to interlink in each armature coil 60.

As shown in FIG. 8, when the electric angle is π, the first stator salient pole portion 62A is in the circumferential direction with respect to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it does not overlap over the entire width, that is, in a position shifted in the circumferential direction. Further, the second stator salient pole portion 62B is located at a position where it overlaps the rotor salient pole portion 44 in the vicinity thereof over the entire width in the circumferential direction when viewed from the radial direction of the rotor 40. In other words, the second overlapping range of the second stator salient pole 62B with respect to the rotor salient pole 44 is larger than the first overlapping range of the first stator salient pole 62A with respect to the rotor salient pole 44. Become. As a result, the first reluctance R1 becomes significantly larger than the second reluctance R2.

As a result, due to the magnetic flux generated from one magnet 48, the second stator salient pole 62B of the first stator core 50A adjacent to one magnetic pole surface of the magnet 48 and the second stator adjacent to the other magnetic pole surface are fixed. A closed-loop magnetic path Mp is formed that passes through the second stator salient pole portion 62B of the child core 50B. For example, the magnet 48 (b) on the upper side in the drawing is the second magnetic path portion 56B of the first stator core 50A (b) → the second stator salient pole portion 62B (e), (f) → the rotor salient pole. Parts 44 (e), 44 (f) → annular base 42 of rotor 40 → rotor salient poles 44 (a), 44 (t) → second stator salient poles 62B (a), 62B (b) → A magnetic path Mp that returns to the original magnet 48 (b) via the magnetic path connecting portion 54 of the second stator core 50B (a) is formed.

The magnetic path Mp is formed so as to interlink in each armature coil 60 in the radial direction. At this time, in the magnetic path Mp, the direction of interlinking in the armature coil 60 is opposite in the radial direction as compared with the case where the electric angle is zero (see FIG. 6).

As shown in FIG. 9, when the electric angle is 3π / 2, the first stator salient pole portion 62A is peripheral to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it overlaps over half the width in the direction. Further, the second stator salient pole portion 62B is positioned so as to overlap the rotor salient pole portion 44 in the vicinity thereof over a half width in the circumferential direction when viewed from the radial direction of the rotor 40. As a result, the first reluctance R1 and the second reluctance R2 have the same magnitude. As a result, a magnetic path Mp similar to that when the electric angle is π / 2 is formed.

As described above, when the electric angle is zero (hereinafter referred to as the first state), the second reluctance R2 is significantly larger than the first reluctance R1 and the electric angle is 3π / 2 (hereinafter referred to as the first state). In the second state), the first reluctance R1 is significantly larger than the second reluctance R2. When the rotor 40 rotates, the first state and the second state are alternately switched.

As shown in FIGS. 6 and 8, in one armature coil 60 (for example, the armature coil 60 (b)), in the first state, a magnetic path Mp interlinking in one direction in the radial direction is formed. In the second state, a magnetic path Mp interlinking with the other in the radial direction is formed. That is, when switching between the first state and the second state, the direction of the magnetic flux interlinking in each armature coil 60 in the radial direction is reversed, and alternating current is induced in each armature coil 60. Power is generated. At this time, AC power of the same phase is generated in each armature coil 60. In this way, in the generator 10, the positions of the plurality of rotor salient poles 44 and the plurality of stator salient poles 62A and 62B are determined so that the first state and the second state are alternately switched.

The operation and effect of the above generator 10 will be described.
In general, the frequency f (Hz) of the generator satisfies the relationship of the following equation (1) between the rotation speed N (r / min) of the rotor and the number of poles P of the generator.
N = 120 × f / P ・ ・ ・ (1)

The present inventor has obtained the finding that in the generator 10 according to the present embodiment, the number obtained by doubling the number of rotor salient poles 44 is the number of poles P of the generator. This finding was obtained by analysis using the structure shown in FIG. In this analysis, the rotation speed N of the rotor 40 was set to 120 (r / min), and the frequency f (Hz) of the power generated by each armature coil 60 was determined. As a result, the frequency f is required to be 40 (Hz), and from the equation (1), the number of poles P of the generator is obtained by doubling the number (20) of the rotor salient poles 44. Was confirmed.

Therefore, in the generator 10 according to the present embodiment, if the rotor salient poles 44 and the stator salient poles 62A and 62B are arranged at predetermined positions, the number of the rotor salient poles 44 increases. The frequency of the electromotive force increases, and even when the rotation speed of the rotor 40 is low, it becomes easy to obtain high-frequency AC power. Since the voltage of the induced electromotive force is proportional to the product of the magnetic flux interlinking the armature coil 60 and the frequency, the fact that a high frequency AC power can be obtained means that a high voltage AC power can be obtained. become.

Further, the first stator salient pole portion 62A and the second stator salient pole portion 62B are provided at positions sandwiching the magnet 48 and the coil slot portion 52, so that the distance between them can be easily separated. Therefore, even if these are excited to different polarities by the magnet 48, it becomes easy to suppress the generation of leakage flux between the first stator salient pole portion 62A and the second stator salient pole portion 62B. Therefore, it becomes easy to reduce the outer diameter dimension of the rotor 40 and the stator 38 of the generator 10 while suppressing the generation of the leakage flux between them. It should be noted that the fact that the generation of the leakage flux between the first stator salient pole portion 62A and the second stator salient pole portion 62B can be suppressed means that the reduction of the magnetic flux interlinking the armature coil 60 is suppressed. Therefore, it becomes easy to obtain a sufficient output voltage by the generator 10.

Further, for example, in a three-phase AC generator in which an armature coil is wound around each of a plurality of salient poles of a stator as described in Japanese Patent Application Laid-Open No. 2012-182961, an electric machine is used as the number of magnetic poles of the rotor increases. The number of child coils increases, which leads to high cost and reduced assemblability. In this regard, in the present embodiment, in order to obtain high-frequency AC power, it is only necessary to increase the number of rotor salient poles 44 without increasing the number of magnets 48 and armature coils 60, so the number of parts is increased accordingly. It can be reduced, and good assembleability can be obtained while keeping the cost low.

Further, in the conventional claw pole type generator, the magnetic flux flowing from the magnet of the rotor to the claw portion of each stator core is changed in the axial direction in the claw portion and then flows toward the root portion of the claw portion. The magnetic path cross-sectional area orthogonal to the magnetic path direction (axial direction) of the claw portion is determined according to the radial thickness and the peripheral length of the claw portion. Here, when the outer diameter dimension is miniaturized without changing the shaft length of the generator, the claw portion of the stator core becomes thinner in the circumferential direction without changing the shaft length, and the gap surface facing the magnet becomes thinner. Moreover, as a result of the decrease in the radial thickness, the magnetic path cross-sectional area at the base of the claw portion becomes small. Therefore, the magnetic flux received by the claw portion of the stator core at the gap surface tends to be concentrated on the root portion of the claw portion having a small magnetic path cross-sectional area, and magnetic saturation is likely to occur at the root portion. As a result, it becomes difficult for the magnetic flux interlinking the armature coil to flow, and it becomes difficult for the generator to obtain a sufficient output voltage.

In this regard, in the generator 10 according to the present embodiment, magnetic flux flows through the stator salient poles 62A and 62B of the stator core 50 in the radial direction instead of the axial direction. The magnetic path cross-sectional area orthogonal to the magnetic path direction (diameter direction) of the stator salient poles 62A and 62B is determined according to the axial length and the peripheral length of the stator salient poles 62A and 62B, and is outside the generator 10. It does not change easily even when the diameter is reduced. Therefore, even when the outer diameter of the generator 10 is reduced, the magnetic path cross-sectional areas of the stator salient poles 62A and 62B can be secured by increasing the axial length of the stator core 50. Therefore, even when the outer diameter of the generator 10 is miniaturized, the generation of magnetic saturation of the stator salient poles 62A and 62B can be suppressed, the decrease of the magnetic flux interlinking the armature coil 50 can be suppressed, and the generator 10 can be suppressed. This makes it easier to obtain a sufficient output voltage.

Further, each time the state is switched between the first state and the second state, the direction of the magnetic path Mp generated by one magnet 48 in the armature coil 60 can be reversed, and the direction is not reversed. The amount of change in the magnetic flux interlinking the child coil 60 can be increased, and it becomes easier to obtain high-voltage AC power. Further, each time the state is switched between the first state and the second state, one magnet 48 can be used to reverse the direction of the magnetic path Mp generated in one armature coil 60, so that the number of magnets 48 can be reversed. It becomes easier to obtain high-voltage AC power while suppressing the above.

Further, each first stator salient pole portion 62A is displaced from the other first stator salient pole portion 62A at an angle equivalent to λ × n, and each second stator salient pole portion 62B is displaced from the other first stator salient pole portion 62B by the first stator protrusion. It deviates from the pole 62A at an angle equivalent to λ × (n + 0.5). Therefore, the relative positions of the stator salient poles 62A and 62B with respect to the rotor salient pole 44 are aligned, the way of changing the magnetic path Mp formed by the magnetic flux generated from each magnet 48 is matched, and each armature coil is matched. With 60, it is possible to easily obtain AC power of the same phase.

Further, since the stator cores 50A and 50B and the rotor core 46 can be formed by laminating a plurality of metal plates, iron loss due to eddy current in a portion through which the main magnetic flux passes can be greatly suppressed.

[Second Embodiment]
FIG. 10 is a cross-sectional view showing the generator 10 according to the second embodiment, and FIG. 11 is a cross-sectional view showing the armature coil 60 of the generator 10. In the example of FIG. 3, a total of 20 rotor salient poles 44 are provided in the rotor 40, but in this example, a total of 18 rotor salient poles 44 are provided. The salient pole pitch λ is 20 ° (= 360 ° / 18).

In the example of FIG. 3, a total of four magnets 48 of the stator 38 and the stator cores 50A and 50B are provided, but in this example, a total of two magnets are provided. Further, in the example of FIG. 3, two first stator cores 50A and two second stator cores 50B are provided, but in this example, one each is provided. Further, in the example of FIG. 3, two first stator salient poles 62A and two second stator salient poles 62B are provided in the first magnetic path portion 56A and the second magnetic path portion 56B. In the example, four are provided. As described above, the number of the rotor salient poles 44 and the stator salient poles 62A and 62B is not particularly limited.

The operation of the generator 10 described above will be described with reference to FIGS. 12 to 15. Each figure shows a state when the rotor 40 is rotated in the direction P by π / 2 at an electric angle. In FIGS. 12 and 14, among the magnetic fluxes flowing through the rotor core 46 and the like, the flow of the main magnetic flux is mainly shown, and the flow of the leakage flux is omitted. Further, FIGS. 13 and 15 show the flow of the leakage flux. In the following, it is assumed that the electric angle is zero when the positional relationship is shown in FIG. 12, and that the electric angles are π / 2, π, and 3π / 2 in FIGS. 13 to 15.

As shown in FIG. 12, when the electric angle is zero, the first stator salient pole portion 62A is in the circumferential direction with respect to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it overlaps over the entire width. The second stator salient pole portion 62B is displaced from the rotor salient pole portion 44 in the vicinity thereof at a position where it does not overlap over the entire width in the circumferential direction, that is, in the circumferential direction when viewed from the radial direction of the rotor 40. In position. In other words, the first overlap range of the first stator salient pole portion 62A with respect to the rotor salient pole portion 44 is larger than the second overlap range of the second stator salient pole portion 62B with respect to the rotor salient pole portion 44. .. As a result, a closed-loop magnetic path Mp is formed so as to radially interlink the inside of each armature coil 60, as in the first embodiment.

As shown in FIG. 13, when the electric angle is π / 2, the first stator salient pole portion 62A is peripheral to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it overlaps over half the width in the direction. Further, the second stator salient pole portion 62B is positioned so as to overlap the rotor salient pole portion 44 in the vicinity thereof over a half width in the circumferential direction when viewed from the radial direction of the rotor 40. In other words, the first overlapping range of the first stator salient pole portion 62A with respect to the rotor salient pole portion 44 and the second overlapping range of the second stator salient pole portion 62B with respect to the rotor salient pole portion 44 are equivalent. .. As a result, a closed-loop magnetic path Mp is formed so as to reciprocate in the radial direction in each armature coil 60 as in the first embodiment.

As shown in FIG. 14, when the electric angle is π, the first stator salient pole portion 62A is in the circumferential direction with respect to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it does not overlap over the entire width, that is, in a position shifted in the circumferential direction. The second stator salient pole portion 62B is located at a position where it overlaps the rotor salient pole portion 44 in the vicinity thereof over the entire width in the circumferential direction when viewed from the radial direction of the rotor 40. In other words, the second overlapping range of the second stator salient pole 62B with respect to the rotor salient pole 44 is larger than the first overlapping range of the first stator salient pole 62A with respect to the rotor salient pole 44. Become. As a result, a closed-loop magnetic path Mp is formed so as to radially interlink the inside of each armature coil 60, as in the first embodiment.

As shown in FIG. 15, when the electric angle is 3π / 2, the first stator salient pole portion 62A is peripheral to the rotor salient pole portion 44 in the vicinity thereof when viewed from the radial direction of the rotor 40. It is in a position where it overlaps over half the width in the direction. Further, the second stator salient pole portion 62B is positioned so as to overlap the rotor salient pole portion 44 in the vicinity thereof over a half width in the circumferential direction when viewed from the radial direction of the rotor 40. As a result, a magnetic path Mp similar to that when the electric angle is π / 2 is formed.

The present inventor has obtained the finding that even in the above generator 10, the number obtained by doubling the number of rotor salient poles 44 becomes the number of poles P of the generator. This finding was obtained by analysis using the structure shown in FIG. In this analysis, the rotation speed N of the rotor 40 was set to 120 (r / min), and the frequency f (Hz) of the power generated by each armature coil 60 was determined. As a result, the frequency f is required to be 36 (Hz), and from the equation (1), the number of poles P of the generator is obtained by doubling the number (18) of the rotor salient poles 44. Was confirmed.

Therefore, also in the generator 10 according to the present embodiment, as in the first embodiment, the frequency of the induced electromotive force increases as the number of the rotor salient poles 44 increases, and even when the rotation speed of the rotor 40 is small. It becomes easier to obtain high-frequency AC power. In other respects as well, the same effect as that of the first embodiment can be obtained.

Although the present invention has been described above based on the embodiments, the embodiments merely show the principles and applications of the present invention. Further, in the embodiment, many modifications and arrangements can be changed without departing from the idea of the present invention defined in the claims.

Although the generator 10 has been described by taking a bicycle generator as an example, its use is not limited to this. Further, when the generator 10 is a bicycle generator, the rotor 40 may be rotatable in conjunction with the rotation of the rotating portion of the bicycle 12. Although the front wheel 22 as a wheel has been described as an example of the rotating portion here, a hub shell, a crank, a pulley of a rear derailleur (chain tensioner), or the like may be used. Further, the generator 10 may be configured as a roller dynamo or the like instead of a hub dynamo. Although the generator 10 is an outer rotor type generator, it may be an inner rotor type generator in which the rotor 40 is arranged on the inner peripheral side of the stator 38.

As for the stator 38, an example in which the first stator core 50A and the second stator core 50B are separately configured has been described, but these may be integrally configured. Further, although the example in which the widths of the stator salient poles 62A and 62B are the same as the width w of the rotor salient pole 44 has been described, the width w of the rotor salient pole 44 or less may be used, or the rotor protrusion The width w of the pole portion 44 or more may be used.

The positions of the rotor salient poles 44 and the stator salient poles 62A and 62B are not limited to the illustrated examples, and are the first state in which the second reluctance is larger than the first reluctance and the first magnetism than the second reluctance. It suffices if it is set so that the second state having a large resistance is alternately switched.

In order to satisfy this condition, in the first state, the first overlapping range of the first stator salient pole portion 62A with respect to the rotor salient pole portion 44 is the rotor salient pole portion of the second stator salient pole portion 62B. It may be larger than the second overlap range with respect to 44. Further, in order to satisfy this condition, in the second state, the second overlapping range may be larger than the first overlapping range.

For example, in FIGS. 6 and 12, when in the first state, the first overlapping range is the range extending over the entire width of the first stator salient pole portion 62A in the circumferential direction, and there is no second overlapping range. .. In addition to this, when in the first state, for example, the first overlapping range is the same as the illustrated example, while the second overlapping range is the rotor salient pole portion in the vicinity of the second stator salient pole portion 62B. It may be a range that overlaps with 44 over a range of half the width or less of the second stator salient pole portion 62B. At this time, the second stator salient pole portion 62B is located at a position displaced in the circumferential direction with respect to one rotor salient pole portion 44 so that the second overlapping range is smaller than the first overlapping range. It will be.

Similarly, in FIGS. 8 and 14, when in the second state, there is no first overlapping range, and the second overlapping range is a range extending over the entire width of the second stator salient pole portion 62B in the circumferential direction. did. In addition to this, when in the second state, for example, the second overlapping range is the same as the illustrated example, while the first overlapping range is the rotor salient pole portion in the vicinity of the first stator salient pole portion 62A. It may be a range that overlaps with 44 over a range of half the width or less of the first stator salient pole portion 62A.

10 ... Generator, 12 ... Bicycle, 22 ... Front wheel (rotor), 26 ... Hub, 38 ... Stator, 40 ... Rotor, 44 ... Rotor salient pole, 46 ... Rotor core, 48 ... Magnet, 50A ... 1st stator core, 50B ... 2nd stator core, 52 ... Coil slot part, 56A ... 1st magnetic path part, 56B ... 2nd magnetic path part, 60 ... Armor coil, 62A ... Stator salient pole part , 62A ... 1st stator salient pole, 62B ... 2nd stator salient pole.

Claims (4)

Rotor and
Circumferentially arranged at intervals, and a plurality of magnets are opposite poles in the circumferential direction becomes the same polarity, and a plurality of stator cores that will be arranged in the circumferential direction on both sides of the magnet, wherein the plurality of stator cores, respectively A stator having an armature coil provided in the coil slot portion and an armature coil wound between the coil slot portions so as to straddle the magnet in the circumferential direction.
The magnet is provided so as to radially divide the plurality of stator cores adjacent to each other on both sides in the circumferential direction of the magnet.
The rotor has a rotor core including a plurality of rotor salient poles formed at intervals in the circumferential direction.
The stator core has a plurality of first stator salient poles and a plurality of second stator salient poles.
The first stator salient pole portion is provided in a magnetic path portion adjacent to one of the coil slot portions in the circumferential direction so as to face the rotor.
The second stator salient pole portion is provided in a magnetic path portion adjacent to the other in the circumferential direction with respect to the coil slot portion so as to face the rotor.
The plurality of rotor salient poles are arranged at positions shifted in the circumferential direction at an angle equivalent to a predetermined angle λ.
The first stator salient pole portion is arranged at a position shifted in the circumferential direction at an angle equivalent to λ × n (n is a natural number of 1 or more) with respect to the other first stator salient pole portion.
The second stator salient pole portion is arranged at a position shifted in the circumferential direction at an angle equivalent to λ × (n + 0.5) with respect to the first stator salient pole portion.
The positions of the plurality of rotor salient poles, the first stator salient pole, and the second stator salient pole are determined so that the first state and the second state are alternately switched.
When in the first state, all the first stator salient poles are positioned so as to overlap the rotor salient poles in the vicinity over the entire width in the circumferential direction, and all the second stators. The salient pole portion is located at a position where it does not overlap with the rotor salient pole portion in the vicinity over the entire width in the circumferential direction.
In the second state, all the first stator salient poles are at positions that do not overlap the rotor salient poles in the vicinity over the entire width in the circumferential direction, and all the second stator poles are fixed. The child salient pole portion is a generator characterized in that it is located at a position where it overlaps the rotor salient pole portion in the vicinity thereof over the entire width in the circumferential direction . The generator according to claim 1, wherein the rotor core and the stator core are formed by laminating a plurality of metal plates in the axial direction of the rotation center of the rotor. The generator according to any one of claims 1 to 2 , wherein the generator is a bicycle generator in which the rotor can rotate in conjunction with the rotation of a rotating portion of the bicycle. The generator according to claim 3 , wherein the generator is a hub dynamo for a bicycle.

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